1. Field of the Invention
The invention relates to a telecommunication interface apparatus and method, and more particularly to an interface apparatus and method for transmitting data between a host computer and a telecommunication network without retiring special host-based computer programs.
2. Description of the Prior Art
Computers today are often used to communicate to other people and computer systems via telecommunication networks and services such as telex, electronic mail, and facsimile (fax) transmissions. To perform this function, special communication programs (or "software") are required in the user's (or "host") computer to meet the requirements of the telecommunication network.
In the present art, to connect a host computer to a telecommunication network, a physical connection of a communication interface (such as a modem or network gateway module) to a port of the host computer is necessary. The communication interface is in turn connected to the telecommunication network (for example, via telephone wires). The computer port is commonly an RS-232 serial interface port, communicating in ASCII, BSC, or SDLC codes with communication protocols varying depending on the brand of computer. Such protocols are typically implemented within the communication interface in the form of ROM-resident software ("firmware"). The communication protocol must include all of the necessary commands and controls to permit the handling of the interface and to transmit or receive data. Similarly, the protocol must include all necessary controls to differentiate between status and control data coming from the interface and data forming a user's message. Higher level communication software uses the command and control structure of the protocol to effectuate telecommunication sessions. An example of one such protocol is the Hayes AT command protocol used in the microcomputer environment. On larger computers, no standard has emerged at this time.
Requiring special communication software resident in the host computer requirement presents an inconvenience for computer users, since not only must they purchase or write such software, but they also have to write or purchase compatible editing or word processing software to generate the messages or files to be transferred. Alternatively, they can write additional software to link such communication software to their existing word processing or editing software.
It is desirable to provide a method for connecting a computer to a telecommunication interface which does not require any special software in the host computer to communicate with the interface. This would reduce the cost, simplify the use, and permit the installation of the telecommunication interface in any host computer while utilizing the host computer's existing programs. Consequently, the training time of users would be dramatically reduced since they would communicate to the telecommunication interface using their existing programs.
The present invention achieves this goal by linking a transmission interface to the printer port of a host computer, and optionally to a workstation port of the host computer. The invention enables communications to be accomplished using existing programs included in most computers. The invention therefore eliminates the need for special host computer resident communication software.